The full-scale war against Ukraine has brought the issue of systemic environmental destruction to the forefront as a tool of modern armed conflict and has given new weight to the concept of ecocide in the context of national and international security. Large-scale damage to ecosystems, industrial facilities, water resources, energy and agricultural infrastructure demonstrates that environmental damage in wartime is not accidental, but structural in nature and causes long-term socio-economic and security consequences. The article considers ecocide as a multidimensional threat that affects environmental sustainability, public health, economic stability and regional security. The study analyzes the regulatory and institutional status of ecocide at the national and international levels. Special attention is paid to the criminalization of ecocide in Ukraine, the practices of recording and investigating environmental crimes in the context of military operations, as well as the problems of international criminal-legal qualification of large-scale environmental damage. The role of the UN system structure and international financial mechanisms in shaping the institutional response, supporting green reconstruction and restoring environmental sustainability is separately considered. The thesis is substantiated about the need to institutionalize ecocide as an element of the global safe architecture and strengthen international mechanisms of responsibility for military environmental damage.